Effect of Perceived Values
Times have changed but the value/price mindset continues. One place I was at a few years ago seemed caught up in the mindset. They hired a young DBA whose expertise was mostly in Visual Basic and SQL Server, and on his recommendation spent a lot of money on hardware and software, dedicated high-end server system, workstation systems, etc. I didn't know then some of the things I know now, and I'd have come up with a rather less pricey solution if asked today. Back then I probably would have come up with yet a third solution involving mostly development on my part and little if any
hardware investment. Shortly after that they started going down the open-source path with Apache and Perl. They probably would have arrived at MySQL or something similar in time, but a corporate mindset is a hard thing to break.
The idea of switching to an open source database for a web application has a lot to do with highering a web experts and then acquiring for him the tools he requests to fulfill his job. But still the web system is viewed as separate from the 'real' data processing, somehow inferior. The OS database is no less efficient or reliable, of course, but unless that is understood by managers or decision makers it matters little. There may be a slow increase over time, the occasional rogue department that switches over, but it's counter to the corporate culture of volume license deals with large software vendors. A lot remains to be seen how the landscape continues to unfold, but there are signs that times are changing, mindsets are changing.